Essential benefit requirements apply mainly to individual and small group plans. The requirements also apply to benefits provided to those newly eligible for Medicaid coverage.

A few of the requirements also affect self-insured plans and large group plans offered by employers. Limits on the maximum out-of-pocket costs a consumer would face each year, for example, would apply to all policies. That amount would be $6,250 for a single policyholder and $12,500 for a family based on this year's rate. The 2014 number is expected to be slightly higher.

The 149-page final rule retains requirements that insurers offer at least one drug per therapeutic category, or the same number as a state's benchmark plan, whichever is greater. Many state benchmark plans require at least two drugs per class.

Responding to concerns from some advocacy groups, the final rule also states that insurers must have procedures to allow patients to get "clinically appropriate" prescriptions not on the plan's list of covered medications.

"This is an improvement," said Stephen Finan, director of policy for the American Cancer Society Cancer Action Network. "It suggests that if you need a drug and that's not on the formulary, you can get it, which was not the case before."

Advocates had wanted the government to require coverage of a broader range of drugs, but insurers and others said requiring many more would raise premium costs. The final rule says "plans are permitted to go beyond the number of drugs offered by the benchmark."